Bodywork Painting Issues
Turbo Mini Forums

Having a 'mare trying to get paint on the rear quarters.

Previously used the same primer and top coat combo on the bare new panels without any issues.

On the rear quarters I put a couple of coats of primer over the existing paint. I then flatted it off and put on a coat of black cellulose top coat with standard thinners.

It immediately reacted and blistered. I thought that I had not dried off the panel enough as it looked like water spotting and followed what could have been wiping sweeps across the panel. So I flatted it all back.

Just had another go and seem to be getting the same sort of problem, but now it seems to be blistering on the boundary between the first layer of new paint and the primer.



Top of the photo is the masking paper, bottom is the unpainted bit, middle has had a single pass with the gun.

Any clues as to what to do to get round this?

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Looks like silicone or wax causing the issue, looks like craters in the paint although hard to tell from the photo.
Thoroughly clean and degrease, then you can buy silicone crater stopper drops to put in the paint. Also I find a couple of very light dust coats will help to avoid this rather than going for it straight away with a heavy coat.

silicone/oil either on the panel/in your air lines or generally conatimainating something. Im far from even respectable at bodywork, but when that happens to me, its sand back and start again can never seem to get round it, except occationally goin nuts with brake cleaner on a rag then lightly dusting a few coats on.

turbo 16v k-series 11.9@118.9 :)

Denis O'Brien.

Thanks guys.

That was a light coat

Following Tom's advice I've found something called "Fish Eye Killer" specifically for the job.

My local paint shop sells something called "barcoat isolator" which seals the coats below.

Both involve a bit of work but less than actually sanding it all back to bare metal.

I'll let you know how I get on.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

did you use any sort of panel wipe or tack rags, do you have a moisture trap and filter for the air lines and did you clean you gun well?

Done now needs redoing lol

Yes, yes and yes

I'm sure that its a reaction with the paint underneath.

You can see from the picture that the blisters follow the line of exposed primer rather than the new layer on top of the primer or the original paint.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

I reckon you should either strip off all the paint and start again or use Lesonal barcoat.

It looks to me as if your new paint is reacting with the coats under the present top layer -at the margins where it is exposed,as you say.

Its a bodge, but I have got round this in the past by heating the panel and then spraying a light coat, so that it dries before it can react, I have even sprayed with a spraygun in one hand and a fan heater in the other -but I don,t accept any responsibility if you do !

I have no doubt the professionals will be horrified at this, but I have been messing about for 40 years with cars and I am a fully paid up founder member of Bodgers Anonymous.

If something is worth doing, it's worth doing half of.

After you degreased it you didnt leave it long enough for the solvent to fully evaporate. Most degreasers have to be wiped on then wiped off again. Also it soaks into the primer - as has happened here and has caused this reaction. Its nothing to do with the paint underneath

Edited by paul wiginton on 1st Jul, 2014.

I seriously doubt it!

Thanks Paul,

That's the best explanation I heard.

I only left it about 10 minutes between using the panel wipe and painting.

I'll have another go in the morning.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

I have fast panel wipe, wipe on and evaporates off within seconds. Never had a problem painting over anything with cellulose, even paint I had previously polished and waxed the hell out of with a light flatting back. The stuff I have is Upol panel wipe.

Just remember that when the panel wipe evaporates it leaves the grease and dirt on the panel which is why you should wipe it off

I seriously doubt it!

Obviously I give it a proper good wipe over the panels with it on but I've never had any problems afterwards in doing just that. I generally panel wipe before I start sanding too so i don't end up sanding any contaminants into the paintwork. Not that I'm after any sort of finish with satin celly, but I'd still be pretty peeved at fixing a reaction afterwards!

What paul said !!

i get this problem when ever i try to spray white paint, never had a problem making a mess in other colours

Yes i moved to the darkside

Instagram @jdm_brett

Dubious about entering the ring with such experienced people, but I was right for the wrong reasons in that I was drying off the panel before painting by applying heat then ?

Yeah that's fine, most smart repair guys either have an infrared heating lamp on the panel or they're wielding a heat gun haha

A dry air line will be as good as anything

I seriously doubt it!

Well, I'm going to go out and have another go before I trip off to the shop to get some chemicals.

Making sure that everything is bone dry first.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Sorted.

I had flatted it back last night so all I had to do this morning was tack rag it.

First coat did not look too good at first but then it seemed to settle. So I put another light coat on it and finally a thicker dryer coat.

All that can be seen is a slight shrinkage of the paint where there is primer below. Nothing that cannot be lost with a bit of elbow grease.

Going to leave it overnight, flat it back with 600 in the morning, then a couple of coats with the high gloss thinners to finish it off.

Thanks for the guidance guys.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Barcoat

If something is worth doing, it's worth doing half of.

Lol

John, I don,t make myself a complete arse on here just to amuse people you know - it is a completely natural talent.

Turned out nice



Just took my time, made sure everything was clean and dry.

Hopefully that's the last bit of painting done.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."